Antimicrobial agents and use thereof

ABSTRACT

Substances which are subject to microbial spoilage are preserved by addition of a cinnamyl phenol, e.g., 2-cinnamylphenol, 4-cinnamyl phenol, 2-methoxy-4-cinnamyl-phenol, 2-cinnamyl-5-methoxy-quinol, etc.

A non-exclusive, irrevocable, royalty-free license in the invention herein described, throughout the world for all purposes of the United States Government, with the power to grant sublicenses for such purposes, is hereby granted to the Government of the United States of America.

This is a division of our co-pending application, Ser. No. 74,485, filed Sept. 22, 1970, issued July 10, 1973 as U.S. Pat. No. 3,745,222.

This invention relates to the preservation of substances which are normally subject to microbial spoilage. The objects of the invention include the provision of novel processes and compositions for accomplishing such preservation. Further objects of the invention will be evident from the following disclosure wherein parts and percentages are by weight unless otherwise specified. The abbreviation ppm used herein refers to parts per million. Temperatures are given in degrees Centigrade. The symbol φ is used herein to designate the phenyl radical.

In accordance with the invention it has been found that certain agents exhibit unexpected antimicrobial activity and are useful for preserving all kinds of materials which are normally subject to microbial spoilage. The agents in question are certain cinnamylphenols, and their antimicrobial activity is unusual and unexpected because it is not shared by closely-related phenol derivatives.

Generically, the agents in accordance with the invention have the structure ##SPC1##

Where at least one but not more than three of the R's are hydroxy radicals, and the remainder of the R's are each independently selected from the group consisting of lower alkyl, lower alkoxy, and hydrogen.

The compounds of the invention are especially useful because they are active against many microorganisms in the categories of bacteria, yeasts, and molds. In other words, the compounds are not just active against one or a few organisms; rather, they display broad-spectrum antimicrobial activity.

Examples of particular compounds within the scope of the invention are given below by way of illustration and not limitation:

    4-Cinnamyl-phenol                                                               (also known as                                                                obtusastyrene)                                                                 2-Cinnamyl-phenol                                                              2-Cinnamyl-4-methyl-                                                             phenol                                                                       2-Cinnamyl-4-methoxy-                                                            phenol                                                                       2-Methyl-4-cinnamyl-                                                             phenol                                                                       2-Methoxy-4-cinnamyl-                                                            phenol                                                                       4-Cinnamyl-resorcinol                                                          2-Cinnamyl-5-methoxy-                                                            quinol                                                                       4-Cinnamyl-pyrogallol                                                     

The compounds of the invention display activities which are equal or even superior to those of widely-used antimicrobial agents. This is illustrated by the following: In general, the compounds of the invention are superior to such known agents as phenol, resorcinol, o-phenyl-phenol, and the alkali metal sorbates and benzoates. For instance, compounds of the invention, at concentrations of 12 to 25 ppm, were found to inhibit the growth of four bacteria (Bacillus cereus, Sarcina lutea, Staphylococcus aureus, and Streptococcus lactis) whereas to achieve the same effect it required 100 to 200 ppm of o-phenyl-phenol, more than 800 ppm of potassium sorbate, and more than 1000 ppm of sodium benzoate.

Alkyl 4-hydroxybenzoates are well known to exhibit potent microbial activity. In general, the compounds of the invention display a superior activity as compared to these benzoates wherein the alkyl group contains less than seven carbon atoms. For instance, whereas the compounds of the invention at a concentration of 12 to 25 ppm will inhibit the growth of the four bacteria noted above, it requires concentrations of 100 to 400 ppm for the same result to be achieved with the C₁ -C₅ alkyl 4-hydroxybenzoates. Moreover, it may be noted that the compounds of the invention have an advantage in that their water-solubility is higher than that of the higher alkyl (e.g., heptyl) 4-hydroxybenzoates, and that the compounds of the invention do not exhibit the strong and unpleasant odor which characterizes the said benzoates. Also, with respect to some microorganisms, the compounds of the invention inhibit growth when applied at levels less than required with the higher alkyl 4-hydroxybenzoates. This is the case, for example, with bacteria such as Acaligenes faecelis and E. coli, yeasts such as Pichia chodati, Hansenula anomala, and Saccharomyces cerevisiae, and molds including Aspergillus flavus, A. niger, Penicillium chrysogenum, Rhizopus senti, Botrytis cinerea, Byssochlamys fulva, and Alternaria sp.

Of the various compounds included within the scope of the invention, the cinnamyl-substituted monophenols display particularly high antibiotic activity against a large variety of different microorganisms, and therefore are preferred with respect to the cinnamyl derivatives of di- or tri-phenols. Coming into special consideration is 4-cinnamyl-phenol because it displays antibiotic activity over a wide range of pH. The cinnamyl derivative of monophenols are also preferred because they are essentially colorless, whereas those derived from di- or tri-phenols exhibit various shades varying from red to brown.

As evident from the explanation immediately following Formula I above, the invention includes compounds wherein there may be nuclear lower alkyl or lower alkoxy substituents in addition to the hydroxy groups. In general, the compounds are preferred wherein such additional substituents are absent or, if present, are in small number, e.g., a total of one to two lower alkyl and/or lower alkoxy substituents. Taking the foregoing facts into consideration, we prefer to employ the compounds of the sub-generic category represented by the formula ##SPC2##

wherein

R' is lower alkyl,

R" is lower alkoxy,

n is an integer from 0 to 2,

m is an integer from 0 to 2, and

the sum of n and m is not more than 2.

The invention encompasses not only the use of any of the above-described agents individually, but also mixtures thereof.

In preserving substances in accordance with the invention, any of the aforesaid agents or mixtures thereof are incorporated with the substance, using an amount of the agent to inhibit microbial growth. Additional conventional treatments such as dehydration, canning, refrigeration, or freezing may be applied to the substance containing the added agent. The incorporation of the agent with the substance may involve a mixing of the substance and the agent-- this is especially suitable where the substance is in liquid or particulate form. Where the substance is in the form of pieces of large dimensions the agent may be incorporated therewith by coating it on the surface of the pieces. For such purpose the agent is preferably dispersed in a carrier-- a liquid such as water, alcohol, water-alcohol blends, oils, or a finely-divided solid such as salt, starch, talc, or the like.

The invention is of wide versatility and can be applied for the preservation of all kinds of substances which are normally subject to microbial spoilage. Typical examples of such substances are listed below by way of example. Foodstuffs such as fruits, vegetables, juices, milk, eggs, meat, fish, grains, cereal products, cheese, etc. Animal glues and mucilages; dextrins; starch pastes and solutions; cosmetic, medicinal, and dental preparations; vitamin preparations; pastes, solutions, or other preparations of natural gums such as tragacanth, Arabic, acacia, karaya, locust bean, agar-agar, pectin, elgin, etc.; fermentation broths, mashes, and residues from fermentation processes; whey; wines and vinegars; animal feeds and ingredients of animal feeds such as fish meals, blood meals, feather meal, meat scraps, bone meal, tankage, grains, and oil-seed meals; proteins and protein hydrolysates; textile printing pastes; paints containing proteins or other spoilable dispersing agents; solutions of bark extracts or other tanning agents; molasses; by-products or wastes that contain potentially valuable carbohydrate, proteinous or fat ingredients such as stick liquor, corn steep liquor, fruit cannery wastes, citrus peels, cull fruit and vegetables, tops of root vegetables, distillers' slops, pulp liquors, wash water from textile de-sizing operations, waste liquors from wool scouring plants, dairy and slaughter house wastes and liquors, etc.

The compounds of the invention may be synthesized by known procedures-- for example, those disclosed by Hurd et al, Jour. Am. Chem. Soc., Vol. 59, pp. 107-109; Barnes et al, Tetrahedron, Vol. 21, pp. 2707-2715; Jurd, Experientia, Vol. 24, pp. 858-860; Jurd, Tetrahedron, Vol. 25, pp. 1407-1416; and Jurd, Tetrahedron Letters No. 33, pp. 2863-2866. Typically, these syntheses involve condensing a selected phenol (phenol itself, a cresol, resorcinol, guaiacol, hydroquinone monomethyl ether, etc.) with cinnamyl bromide or cinnamyl alcohol.

The invention is further demonstrated by the following illustrative examples. For comparative purposes, various compounds, including some of known antimicrobial activity, are included in the reported experiments.

EXAMPLE 1

A series of compounds were assayed for effectiveness against bacteria, molds, and yeasts, using the following test procedure.

All compounds were tested at a concentration of 500 ppm. (w/v). Plates were prepared by adding a measured amount of the candidate compound (in an appropriate solvent, i.e., acetone, ethanol, or water) to 10 ml. of sterilized medium, mixing thoroughly, pouring into 60 × 15 mm. Petri dishes, and allowing the gel to set. The plates were then inoculated with the test organisms. In the case of bacteria and yeasts the inoculation was done by Lederberg's replica plating technique, applying nine bacteria or seven yeasts on each plate. In the case of molds, drops of homogenized culture were placed on the surface of the plates, applying three to four molds per plate.

The media used were: plate count agar (Difco) for bacteria; potato dextrose agar (Difco) for yeasts and molds.

Control plates were also prepared containing the media plus the same solvent used for the candidate agents and inoculated with the same organisms.

The plates were incubated at 28° C. for one to five days and evaluated by comparison with the controls.

The results are expressed on the basis:

+ for effective to inhibit growth

± for not completely effective; faint growth occurs

- for ineffective; growth occurs

The results are summarized in the following tables.

                                      Table I                                      __________________________________________________________________________     Activity of Various Compounds (at conc. of 500 ppm)                            Against Bacteria                                                               __________________________________________________________________________              4-Cinna-                                                                             4-Cinna-                                                                             4-Cinna-                                                                             2-Cinna-                                                                             2-Cinna-                                                                             Cinnamyl-                                                                            Phenol                                                                             Resor-                                                                             Pyro-                                                                              Methoxy-                       myl-phenol                                                                           myl-resor-                                                                           myl-pyro-                                                                            myl-5-me-                                                                            myl-5-me-                                                                            eugenol   cinol                                                                              gallol                                                                             quinol                               cinol gallol                                                                               thoxy-qui-                                                                           thoxy-qui-                                                               nol   none                                          __________________________________________________________________________     Bacillus cereus                                                                         +     +     +     +     -     +     -   -   +   +                     Sarcina lutea                                                                           +     +     +     +     -     -     -   -   +   -                     Staphylococcus                                                                 aureus   +     +     +     +     -     -     -   -   +   -                     Streptococcus                                                                  lactis   +     +     +     +     -     +     -   -   +   +                     Acaligenes                                                                     faecalis +     +     +     +     -     -     -   -   +   +                     Escherichia                                                                    coli     +     +     ±  -     -     -     -   -   +   +                     Pseudomones                                                                    aeruginosa                                                                              -     -     +     -     -     -     -   -   +   +                     Salmonella                                                                     typhimurium                                                                             -     +     ±  -     -     -     -   -   +   -                     Serratia                                                                       marcescens                                                                              -     -     ±  -     -     -     -   -   ±                                                                               -                     __________________________________________________________________________

                                      Table II                                     __________________________________________________________________________     Activity of Various Compounds (at conc. of 500 ppm)                            Against Yeasts                                                                 __________________________________________________________________________               4-Cinna-                                                                             4-Cinna-                                                                             4-Cinna-                                                                             2-Cinna-                                                                             2-Cinna-                                                                             Cinnamyl-                                                                            Phenol                                                                             Resor-                                                                             Pyro-                                                                             Methoxy-                        myl-phenol                                                                           myl-resor-                                                                           myl-pyro-                                                                            myl-5-me-                                                                            myl-5-me-                                                                            eugenol   cinol                                                                              gal-                                                                              quinol                                cinol gallol                                                                               thoxy-qui-                                                                           thoxy-qui-          lol                                                  nol   none                                         __________________________________________________________________________     Zygosacchomyces                                                                japonicus +     +     +     +     +     -     -   -   +  -                     Candida tropicalis                                                                       +     +     +     +     +     +     -   -   +  +                     Pichia chodati                                                                           +     +     +     -     -     -     -   -   -  -                     Hansenula anomala                                                                        +     +     +     -     -     -     -   -   -  -                     Saccharomyces                                                                  cerevisiae                                    -   -   +                        Saccharomyces                                                                  mellis    +     +     +     +     +     -                +                     Torula utilis                                                                            +     +     +     -           -     -   -   +                        Hansenula melliqui                                                                       +     +     +     +     -                                            Candida chalmersi                                                                        +     +     +     +     +     +                +                     Saccharomyces                                                                  rosei     +     +     +     +     -     -                -                     Zygosaccharomyces                                                              barkeri   +     +     +     +     -     -                -                     __________________________________________________________________________

                                      Table III                                    __________________________________________________________________________     Activity of Various Compounds (at conc. of 500 ppm)                            Against Molds                                                                  __________________________________________________________________________               4-Cinna-                                                                             4-Cinna-                                                                             4-Cinna-                                                                             2-Cinna-                                                                             2-Cinna-                                                                             Cinnamyl-                                                                            Phenol                                                                             Resor-                                                                             Pyro-                                                                             Methoxy-                        myl-phenol                                                                           myl-resor-                                                                           myl-pyro-                                                                            myl-5-me-                                                                            myl-5-me-                                                                            eugenol   cinol                                                                              gal-                                                                              quinol                                cinol gallol                                                                               thoxy-qui-                                                                           thoxy-qui-          lol                                                  nol   none                                         __________________________________________________________________________     Aspergillus flavus                                                                       +     +     +     -     -     -     ±                                                                               -   -  -                     Aspergillus niger                                                                        +     +     +     -     -     -     ±                                                                               -   -  -                     Penicillium                                                                    chrysogenum                                                                              +     +     +     -     -     -     -   -   ±                                                                              -                     Rhizopus senti                                                                           +     +     +     -     -     -     -          -                     Botrytis cinerea                                                                         +     +     +     -           -     +   -   +                        Byssochlamys fulva                                                                       +     +     +     +     -     -     ±                                                                               +   +  -                     Alternaria sp.                                                                           +     +     +     -           -     ±                                                                               +   +                        __________________________________________________________________________

EXAMPLE 2

A series of compounds were assayed for effectiveness against bacteria, molds, and yeasts as set forth in Example 1, except that in this case the assays were conducted with varying amounts of each compound to determine the minimum concentration thereof required to inhibit growth.

The results are set forth in the following tables.

                                      Table IV                                     __________________________________________________________________________     Minimal Inhibitory Concentrations (in ppm.) of Various                         Compounds Against Bacteria                                                     __________________________________________________________________________              4-Cinna-                                                                             2-Cinna-                                                                             2-Cinna-                                                                             2-Methyl-                                                                             2-Cinna-                                                                             Ortho-                                                                              Potassi-                                                                            Sodium                                myl-phe-                                                                             myl-phe-                                                                             myl-4-me-                                                                            4-cinna-                                                                              myl-4-me-                                                                            phenyl-                                                                             um sor-                                                                             benzo-                                nol   nol   thoxy-phe-                                                                           myl-phe-                                                                              thyl-phe-                                                                            phenol                                                                              bate ate                                               nol   nol    nol                                          __________________________________________________________________________     Bacillus cereus                                                                         25    12    25    12     12    100- >800 >1000                                                                200                                    Sarcina lutea                                                                           25    25    25    12     12    200  do.  do.                          Staphylococcus                                                                 aureus   25    25    25    12     12    200  do.  do.                          Streptococcus                                                                  lactis   25    12    25    12     12    100- do.  do.                                                                   200                                   Acaligenes                                                                     faecalis  50-  >200  >200  >200   >200  100- do.  do.                                    100                           200                                    Escherichia coli                                                                         50-  >200  >200  >200   >200  100- do.  do.                                    100                           200                                    __________________________________________________________________________

                                      Table V                                      __________________________________________________________________________     Minimal Inhibitory Concentrations (in ppm.) of Various                         Compounds Against Yeasts                                                       __________________________________________________________________________               4-Cinna-                                                                             2-Cinna-                                                                             2-Cinna-                                                                             2-Methyl-                                                                             2-Cinna-                                                                             o-   Potassi-                                                                            Sodium                                myl-phe-                                                                             myl-phe-                                                                             myl-4-me-                                                                            4-cinna-                                                                              myl-4-me-                                                                            phenyl-                                                                             um sor-                                                                             benzo-                                nol   nol   thoxy-phe-                                                                           myl-phe-                                                                              thyl-phe-                                                                            phenol                                                                              bate ate                                               nol   nol    nol                                         __________________________________________________________________________     Zygosaccharomyces                                                              japonicus 12    12    25    12     12    100- 800  >1000                                                                200                                   Candida tropicalis                                                                       12    12    50    25     25    100  200- 250-                                                                      400  500                         Pichia chodati                                                                           25    50    >200  200    >200  100  800  >1000                       Hansenula anomala                                                                        50    50     100  100    50    100- 800  do.                                                                  200                                   Saccharomyces                                                                  cerevisiae                                                                               25    25    50    25     25    100- 800  do.                                                                  200                                   Torula utilis                                                                            50    50    >200  100    >200  100- 800  do.                                                                  200                                   __________________________________________________________________________

                                      Table VI -                                   Minimal Inhibitory Concentrations (in ppm.) of Various                         Compounds Against Molds                                                        __________________________________________________________________________               4-Cinna-                                                                             2-Cinna-                                                                             2-Cinna-                                                                             2-Methyl-                                                                             2-Cinna-                                                                             o-   Potassi-                                                                            Sodium                                myl-phe-                                                                             myl-phe-                                                                             myl-4-me-                                                                            4-cinna-                                                                              myl-4-me-                                                                            phenyl-                                                                             um sor-                                                                             benzo-                                nol   nol   thoxy-phe-                                                                           myl-phe-                                                                              thyl-phe-                                                                            phenol                                                                              bate ate                                               nol   nol    nol                                         __________________________________________________________________________     Aspergillus flavus                                                                       100   100   >200  >200   >200  100  >800 >1000                       Aspergillus niger                                                                        50    100   >200  >200   >200  100  do.  do.                         Penicillium                                                                    chrysogenum                                                                              50    25-   200   50     100    50  do.  do.                                         50                                                             Rhizopus senti                                                                            6    50    >200  50     100   100  200  500                         Botrytis cinerea                                                                         25-   12-   200   50     25    12-  200  500                                   50    25                        25                                   Byssochlamys fulva                                                                       25    25    50    25     25     50  >800 >1000                       Alternaria sp.                                                                           25    25    100   50     100    50  400  500                         __________________________________________________________________________

                                      Table VII                                    __________________________________________________________________________     Minimal Inhibitory Concentrations (in ppm.) of                                 4-Cinnamyl-phenol and Several Alkyl 4-Hydroxybenzoates Against                 Bacteria, Yeasts, and Molds                                                    __________________________________________________________________________                4-Cinna-                                                                             Heptyl-4-                                                                            Amyl 4-                                                                             n-Butyl 4-                                                                            n-Propyl 4-                                                                            Ethyl 4-                                                                             Methyl 4-                                myl-phe-                                                                             hydroxy-                                                                             hydroxy-                                                                            hydroxy-                                                                              hydroxy-                                                                               hydroxy-                                                                             hydroxy-                                 nol   benzoate                                                                             benzoate                                                                            benzoate                                                                              benzoate                                                                               benzoate                                                                             benzoate                      __________________________________________________________________________     Bacillus cereus                                                                           25    12    100  200    400     >200  >200                          Sarcina lutea                                                                             25    12    100  200    400     do.   do.                           Staphylococcus                                                                 aureus     25    12    100  200    400     do.   do.                           Streptococcus                                                                  lactis     25    12    100  200    400     do.   do.                           Acaligenes faecalis                                                                        50-100                                                                              >200  >200 200    400     do.   do.                           Escherichia coli                                                                           50-100                                                                              >200  do.  >200   400     do.   do.                           __________________________________________________________________________     Zygosaccharomyces                                                              japonicus  12    12-25  50  100    100-200 200   do.                           Candida tropicalis                                                                        12    12-25  50  100    200     200   do.                           Pichia chodati                                                                            25    >200  100  100    200-400 >200  do.                           Hansenula anomala                                                                         50    >200  100  100    200-400 do.   do.                           Saccharomyces                                                                  cerevisiae 25    100    50  100    200     do.   do.                           Torula utilis                                                                             50    25    100  100    200     do.   do.                           __________________________________________________________________________     Aspergillus flavus                                                                        100   >200  100  200    200     do.   do.                           Aspergillus niger                                                                         50    do.   100  200    200     do.   do.                           Penicillium                                                                    chrysogenum                                                                               50    do.   100  100    200     do.   do.                           Rhizopus senti                                                                            6     25     50  100    200     do.   do.                           Botrytis cinerea                                                                          25-50  50-100                                                                               50  100    100-200 100   100                           Byssochlamys fulva                                                                        25    >200  100  100    200     200   >200                          Alternaria sp.                                                                            25     50-100                                                                               50   50    100-200 100   >200                          __________________________________________________________________________

EXAMPLE 3

Two compounds (4-cinnamyl-phenol and 4-cinnamyl-resorcinol) were assayed for effectiveness against bacteria, molds, and yeasts, except that in this case the assays were conducted at different concentrations of each compound and at different pH's in order to determine the minimum concentration of each compound required to inhibit growth at the particular pH.

The results are tabulated below.

                                      Table VIII                                   __________________________________________________________________________     Effect of pH on Minimal Inhibitory Concentration (ppm.)                        of 4-Cinnamyl-phenol and 4-Cinnamyl-resorcinol                                 __________________________________________________________________________               4-Cinnamyl-phenol     4-Cinnamyl-resorcinol                          __________________________________________________________________________               pH 7                                                                               pH 6                                                                               pH 5                                                                               pH 4                                                                               pH 3  pH 7                                                                               pH 6                                                                               pH 5                                                                               pH 4                                                                               pH 3                           __________________________________________________________________________     Bacillus cereus                                                                          25  25  25  12.5      200 200 100 6.25                               Sarcina lutea                                                                            25  25  25  12.5      100 100  50 25                                 Staphylococcus                                                                 aureus    25  25  25  25        100 100  50 25                                 Streptococcus                                                                  lactis    25  25  25  25        100 100  50 25                                 Acaligenes                                                                     faecalis  50  25  25  25        200 200 100 25                                 Escherichia coli                                                                         25  50  50  25        100 200 100 50                                 __________________________________________________________________________     Zygosaccharomyces                                                              japonicus     12.5                                                                               12.5                                                                               12.5                                                                               12.5      100  50 50  50                             Candida                                                                        tropicalis    25  25  25  12.5       75  50 50  50                             Pichia chodati                                                                               50  50  25  12.5      100 150 100 50                             Hansenula anomala                                                                            50  50  50  25        100 100 100 75                              Saccharomyces                                                                 cerevisiae    25  25  25  12.5       50  50 100 50                             Geotrichum sp.                                                                 Torula utilis 50  50  37.5                                                                               25         75  50 75  50                             __________________________________________________________________________     Aspergillus                                                                    flavus        100 100 100 50        200 200 200 100                            Aspergillus niger                                                                            100 100 75  37.5      200 200 100 100                            Penicillium                                                                    chrysogenum   50  50  50  12.5      100 100 50  50                             Rhizopus senti                                                                               25  25  25  12.5      100 100 100 50                             Botrytis cinerea                                                                             25  25  25  12.5      100 100 75  50                             Byssochlamys                                                                   fulva         25  25  25  12.5      100 100 75  50                             Alternaria sp.        50  12.5              75  50                             __________________________________________________________________________

EXAMPLE 4

Samples of fruit juice (grape and apple) with and without added 4-cinnamyl-phenol were inoculated with cultures of wild yeast or pure wine yeast (S. cerevisiae) and held at room temperature. The inoculated juices were observed at intervals to detect the time at which fermentation (gas production) began. This is a measure of microbial activity-- where the organisms multiply freely, the time for initiation of fermentation is short; conversely, where microbial growth is inhibited the time for initiation of fermentation is long or does not occur at all.

The results are tabulated below.

                                      Table IX                                     __________________________________________________________________________     Influence of 4-Cinnamyl-phenol on Fermentation of Fruit Juice Inoculated       with Yeasts                                                                    __________________________________________________________________________                     Amount of                                                                            Time for initiation of fermentation, hours               Run                                                                               Substrate                                                                             Inoculum                                                                             inoculum,                                                                            Zero                                                                               12.5 ppm                                                                             25 ppm                                                                               50 ppm                                                                               100 ppm                                                                              200 ppm.                                     cells/ml.                                                                            4-CP                                                                               of 4-CP                                                                              of 4-CP                                                                              of 4-CP                                                                              of 4-CP                                                                              of 4-CP                      __________________________________________________________________________     1  Grape juice                                                                           Wild yeast                                                                           10.sup.7                                                                              7  n.d.  12    n.d.  44    n.d.                         2  do.    do.   10.sup.3                                                                             17  17    30     62   >96   n.d.                         3  do.    Wine yeast                                                                           10.sup.5                                                                             12  22    45    146   ∞                                                                              ∞                      4  do.    do.   10.sup.2                                                                             41  75    ∞                                                                              ∞                                                                              ∞                                                                              ∞                      5  Apple juice                                                                           Wine yeast                                                                           10.sup.5                                                                             46  42    76    ∞                                                                              ∞                                                                              ∞                      __________________________________________________________________________      Explanation of symbols:                                                        4-CP designates 4-cinnamyl-phenol                                              n.d. means not determined                                                      ∞ means that fermentation did not occur; the organisms had been          destroyed.                                                                

Having thus described the invention what is claimed is:
 1. A composition of matter comprising -a. a major proportion of a substance normally subject to microbial spoilage, and b. a minor proportion, sufficient to inhibit microbial growth, of 2-methoxy-4-cinnamyl-phenol.
 2. A composition of matter comprising -a. a major proportion of a substance normally subject to microbial spoilage, and b. a minor proportion, sufficient to inhibit microbial growth, of 2-cinnamyl-4-methoxy-phenol. 